[PATCH 2/2][SRU][P] drm/amdkfd: use GTT for VRAM on APUs only if GTT is larger

[You-Sheng Yang]

From: Alex Deucher <alexander.deucher at amd.com>

BugLink: https://bugs.launchpad.net/bugs/2120454

If the user has configured a large carveout on a small APU,
only use GTT for VRAM allocations if GTT is larger than
VRAM.

v2: fix reversed check (Philip)

Reviewed-by: Mario Limonciello <mario.limonciello at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
(cherry picked from commit 759e764f7d587283b4e0b01ff930faca64370e59)
Signed-off-by: You-Sheng Yang <vicamo.yang at canonical.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 0b1c89068455b..df46a144b2ee6 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1978,8 +1978,10 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
 	DRM_INFO("amdgpu: %uM of GTT memory ready.\n",
 		 (unsigned int)(gtt_size / (1024 * 1024)));
 
-	if (adev->flags & AMD_IS_APU)
-		adev->apu_prefer_gtt = true;
+	if (adev->flags & AMD_IS_APU) {
+		if (adev->gmc.real_vram_size < gtt_size)
+			adev->apu_prefer_gtt = true;
+	}
 
 	/* Initialize doorbell pool on PCI BAR */
 	r = amdgpu_ttm_init_on_chip(adev, AMDGPU_PL_DOORBELL, adev->doorbell.size / PAGE_SIZE);
-- 
2.50.0